In an ink jet recording method, recording is generally carried out by jetting fine drops of ink using a variety of mechanisms so as to form images on a recording paper. Therefore, the recording method of ink jet type has advantages in that it is less noisy, can provide full-color prints with ease and enables high-speed printing, compared with the recording method of dot impact type.
For the paper used in such an ink jet recording method, it is usually required to have properties of (1) ensuring high-speed drying of ink, (2) being free from cissing, feathering and overflowing of ink, (3) providing recorded images of high optical density, and (4) causing no rippling trouble upon absorption of ink, and so on. It has already been proposed to prepare ink jet recording papers partaking all the properties mentioned above by the use of a cast coating method (e.g., in Japanese Tokkai Sho 62-95285, Japanese Tokkai Sho 62-264391 and Japanese Tokkai Hei 02-274587, wherein the term "Tokkai" as used herein means an "unexamined published patent application").
In addition, ink jet printers have had remarkable development in recent years, so that they have come to ensure considerable colorfulness and vividness in the recorded images. Thus, recording media also have been required to be higher grade merchandise. As matters now stand, it is known that higher grade recorded image which can give such a feeling of higher quality as those provided by photography or high grade printed matter can be obtained by choosing a recording medium having a glossy surface.
However, the need for reduction in running cost has also grown in proportion as prices of ink jet printers have declined. Since most of glossy recording media on the market use as their substrates more expensive materials, such as plastic films or laminated papers, they cannot meet the aforesaid need.
In contrast to the recording media on the market in which films or the like are used as substrate, cast-coated paper uses low-priced paper as a substrate and can be prepared in a relatively simple process, so that it has the advantage of a substantially lower cost. Further, as the recording side of cast-coated paper can be rendered glossy, the cast-coated paper is suitable for ink jet recording paper which can give a feeling of high quality and can provide high grade recorded images at a lower price.
The cast-coated paper mentioned above is a highly glossy coated paper prepared by pressing a coated layer comprising a pigment containing a synthetic silica as main component and a water base binder against a specular surface-finished metal surface while the coated layer is in a wet condition, and reproducing the specular surface on the surface of the coated layer simultaneously with drying of the coated layer.
In general, cast-coated paper improves its ink-cissing and feathering properties, dot shape and gloss on the recorded surface by containing therein casein as a water base binder, and utilizing a pigment having a large specific surface area or controlling a void content therein (Japanese Tokkai Hei 06-72017, etc.). In this case, however, the glossy part of cast-coated paper swells by the contact with water base ink. Thus, the cast-coated paper suffers a defect that the gloss in an image area becomes lower than that in a non-image area when cast-coated paper undergoes ink jet recording.